( function () {
class GeometryUtils {
  /**
   * Generates 2D-Coordinates in a very fast way.
   *
   * Based on work by:
   * @link http://www.openprocessing.org/sketch/15493
   *
   * @param center     Center of Hilbert curve.
   * @param size       Total width of Hilbert curve.
   * @param iterations Number of subdivisions.
   * @param v0         Corner index -X, -Z.
   * @param v1         Corner index -X, +Z.
   * @param v2         Corner index +X, +Z.
   * @param v3         Corner index +X, -Z.
   */
  static hilbert2D(center = new THREE.Vector3(0, 0, 0), size = 10, iterations = 1, v0 = 0, v1 = 1, v2 = 2, v3 = 3) {
    const half = size / 2;
    const vec_s = [new THREE.Vector3(center.x - half, center.y, center.z - half), new THREE.Vector3(center.x - half, center.y, center.z + half), new THREE.Vector3(center.x + half, center.y, center.z + half), new THREE.Vector3(center.x + half, center.y, center.z - half)];
    const vec = [vec_s[v0], vec_s[v1], vec_s[v2], vec_s[v3]]; // Recurse iterations

    if (0 <= --iterations) {
      const tmp = [];
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert2D(vec[0], half, iterations, v0, v3, v2, v1));
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert2D(vec[1], half, iterations, v0, v1, v2, v3));
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert2D(vec[2], half, iterations, v0, v1, v2, v3));
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert2D(vec[3], half, iterations, v2, v1, v0, v3)); // Return recursive call

      return tmp;
    } // Return complete Hilbert Curve.


    return vec;
  }
  /**
   * Generates 3D-Coordinates in a very fast way.
   *
   * Based on work by:
   * @link http://www.openprocessing.org/visuals/?visualID=15599
   *
   * @param center     Center of Hilbert curve.
   * @param size       Total width of Hilbert curve.
   * @param iterations Number of subdivisions.
   * @param v0         Corner index -X, +Y, -Z.
   * @param v1         Corner index -X, +Y, +Z.
   * @param v2         Corner index -X, -Y, +Z.
   * @param v3         Corner index -X, -Y, -Z.
   * @param v4         Corner index +X, -Y, -Z.
   * @param v5         Corner index +X, -Y, +Z.
   * @param v6         Corner index +X, +Y, +Z.
   * @param v7         Corner index +X, +Y, -Z.
   */


  static hilbert3D(center = new THREE.Vector3(0, 0, 0), size = 10, iterations = 1, v0 = 0, v1 = 1, v2 = 2, v3 = 3, v4 = 4, v5 = 5, v6 = 6, v7 = 7) {
    // Default Vars
    const half = size / 2;
    const vec_s = [new THREE.Vector3(center.x - half, center.y + half, center.z - half), new THREE.Vector3(center.x - half, center.y + half, center.z + half), new THREE.Vector3(center.x - half, center.y - half, center.z + half), new THREE.Vector3(center.x - half, center.y - half, center.z - half), new THREE.Vector3(center.x + half, center.y - half, center.z - half), new THREE.Vector3(center.x + half, center.y - half, center.z + half), new THREE.Vector3(center.x + half, center.y + half, center.z + half), new THREE.Vector3(center.x + half, center.y + half, center.z - half)];
    const vec = [vec_s[v0], vec_s[v1], vec_s[v2], vec_s[v3], vec_s[v4], vec_s[v5], vec_s[v6], vec_s[v7]]; // Recurse iterations

    if (--iterations >= 0) {
      const tmp = [];
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert3D(vec[0], half, iterations, v0, v3, v4, v7, v6, v5, v2, v1));
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert3D(vec[1], half, iterations, v0, v7, v6, v1, v2, v5, v4, v3));
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert3D(vec[2], half, iterations, v0, v7, v6, v1, v2, v5, v4, v3));
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert3D(vec[3], half, iterations, v2, v3, v0, v1, v6, v7, v4, v5));
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert3D(vec[4], half, iterations, v2, v3, v0, v1, v6, v7, v4, v5));
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert3D(vec[5], half, iterations, v4, v3, v2, v5, v6, v1, v0, v7));
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert3D(vec[6], half, iterations, v4, v3, v2, v5, v6, v1, v0, v7));
      Array.prototype.push.apply(tmp, GeometryUtils.hilbert3D(vec[7], half, iterations, v6, v5, v2, v1, v0, v3, v4, v7)); // Return recursive call

      return tmp;
    } // Return complete Hilbert Curve.


    return vec;
  }
  /**
   * Generates a Gosper curve (lying in the XY plane)
   *
   * https://gist.github.com/nitaku/6521802
   *
   * @param size The size of a single gosper island.
   */


  static gosper(size = 1) {
    function fractalize(config) {
      let output;
      let input = config.axiom;

      for (let i = 0, il = config.steps; 0 <= il ? i < il : i > il; 0 <= il ? i++ : i--) {
        output = '';

        for (let j = 0, jl = input.length; j < jl; j++) {
          const char = input[j];

          if (char in config.rules) {
            output += config.rules[char];
          } else {
            output += char;
          }
        }

        input = output;
      }

      return output;
    }

    function toPoints(config) {
      let currX = 0,
          currY = 0;
      let angle = 0;
      const path = [0, 0, 0];
      const fractal = config.fractal;

      for (let i = 0, l = fractal.length; i < l; i++) {
        const char = fractal[i];

        if (char === '+') {
          angle += config.angle;
        } else if (char === '-') {
          angle -= config.angle;
        } else if (char === 'F') {
          currX += config.size * Math.cos(angle);
          currY += -config.size * Math.sin(angle);
          path.push(currX, currY, 0);
        }
      }

      return path;
    } //


    const gosper = fractalize({
      axiom: 'A',
      steps: 4,
      rules: {
        A: 'A+BF++BF-FA--FAFA-BF+',
        B: '-FA+BFBF++BF+FA--FA-B'
      }
    });
    const points = toPoints({
      fractal: gosper,
      size: size,
      angle: Math.PI / 3 // 60 degrees

    });
    return points;
  }

}

THREE.GeometryUtils = GeometryUtils;
} )();
